[Epidemiological surveillance of blood donors and residual risk of blood-borne infections in France, 2001 to 2003]. / Surveillance épidémiologique des donneurs de sang homologues et risque résiduel en France entre 2001 et 2003.

The national surveillance of French blood donors is performed by the Institut de Veille Sanitaire and the National Reference Center for Hepatitis B and C in transfusion in collaboration with the Etablissement Français du Sang and the Army blood center. The main objectives of this surveillance are to evaluate trends in prevalence and incidence rates of blood-borne infections in the blood donor population, to identify routes of contamination and to assess residual risk. This exhaustive surveillance also contributes to evaluate the blood donor selection and the impact of measures taken to prevent infections in the general population. The analyse of the database of all blood donations obtained from 2001 to 2003 has shown that prevalence rates were stable in the study period (0.60 per 10(4) donors for HIV, 8.0 per 10(4) donors for HCV, 1.8 per 10(4) first-time donors for HBs Ag and 0.56 per 10(4) donors for HTLV), The incidence rate of HIV and HBV (1 per 10(5) person-years) was three-times higher than for HCV (0.35 per 10(5) person-years) and eleven times higher than for HTLV (0.09 per 10(5) person-years). At least, the residual risk of transfusion-transmitted viral infections is very low: 1/3,150,000 donations for HIV, 1/10,000,000 donations for HCV and 1/640,000 donations for HBV. The yield of Nucleic Acid Testing (NAT) is limited since only 2 donations for HIV and 3 for HCV which were negative for antibodies were discarded thank to the NAT.

Efficacy of HCV core antigen detection during the preseroconversion period.

BACKGROUND: The purpose of this study was to compare the performances of HCV core antigen (HCV Ag) testing with HCV RNA detection during the preseroconversion period. STUDY DESIGN AND METHODS: Six HCV antibody (HCV Ab)-negative and HCV RNA-positive blood samples from 6 donors and 135 serial samples from 28 patients who had undergone hemodialysis, collected a mean of 90 days before the detection of HCV Ab, were tested by ELISA for the detection of HCV Ag and by PCR to quantify HCV RNA. RESULTS: Five of the six donors were positive for HCV Ag. The donor with a negative HCV Ag test had the lowest viral load. In the hemodialysis patients, the 43 first specimens of the series were HCV RNA negative. Of the 92 specimens that were HCV RNA positive, 81 (88%) were positive for HCV Ag. Among the 74 samples with more than 10(5) RNA copies, 71 (96%) were HCV Ag positive. Average time from first viremic bleed to first HCV Ag-positive bleed was estimated at 2.0 days and that to first HCV Ab-positive bleed at 50.8 days. CONCLUSION: HCV Ag testing permits the detection of an HCV infection about 1.5 months earlier than the HCV Ab screening tests and an average of only 2 days later than quantitative HCV RNA detection in individual specimens.

Hepatitis C virus (HCV) infection in haemodialysed patients: HCV-RNA and anti-HCV antibodies (third-generation assays).

Samples from 128 haemodialysed patients were tested by anti-HCV 2nd- and 3rd-generation assays from Ortho: 53 were positive by ELISA 2.0 and 54 (42%) by ELISA 3.0. The 54 anti-HCV-positive patients were tested by RIBA-2 and RIBA-3 and by PCR for the detection of HCV-RNA: 46 of the 47 patients (98%) reactive by RIBA-2 and 48 of the 51 patients (94%) reactive by RIBA-3 were HCV-RNA positive. Three patients with RIBA-3 indeterminate results were HCV-RNA negative. Among the 74 anti-HCV negative patients, 29 were tested by PCR with negative results. Two distinct episodes of hepatitis C have been observed in two patients during the follow-up and 44 of the 50 patients (88%) known positive for anti-HCV since at least 1989 were still viraemic in 1993. A very high correlation was found between anti-HCV antibodies reactive by RIBA and the presence of HCV-RNA. A lack of protection after a resolved infection and a high frequency of chronic disease have been observed as well as a reinfection or a reactivation of the infection in two patients.

Anti-hepatitis C virus (anti-HCV) seroconversion in patients undergoing hemodialysis: comparison of second- and third-generation anti-HCV assays.

BACKGROUND: The results obtained in sequential specimens from recently infected subjects generally provide the best means of comparing the sensitivity of assays. STUDY DESIGN AND METHODS: The sensitivity of second- and third-generation assays for antibody to hepatitis C virus (HCV) was compared on sequential specimens, generally collected at monthly intervals from 45 patients undergoing hemodialysis who seroconverted for HCV between 1980 and 1990. RESULTS: Fifteen patients (33%) were positive earlier in the third-generation enzyme-linked immunosorbent assay (ELISA), with a mean difference of 17 days (range, 7-30) between the last negative and the first positive specimens. At the first rise in alanine aminotransferase, and at its peak, 63 and 91 percent of the patients, respectively, were anti-HCV positive in the third-generation ELISA. Third-generation recombinant immunoblot assay (RIBA) reacted at the same time as third-generation ELISA. Of the first specimens that were positive in second-generation ELISA, 44 percent reacted and 56 percent were indeterminate in third-generation RIBA, while 10 percent reacted, 72 percent were indeterminate, and 18 percent did not react in second-generation RIBA. From the beginning to the end of the follow-up, antibody to c33c was the most prevalent, followed in descending order by antibody to c22-3, antibody to c100-3, and antibody to NS5: 56, 54, 26, and 18 percent, respectively, at time 0, and 100, 86, 83, and 31 percent, respectively, 12 months later. CONCLUSION: Third-generation assays (both ELISA and RIBA) were more sensitive than second-generation assays in the diagnosis of HCV infection, in that positive results were obtained earlier and a higher proportion of specimens were confirmed positive in RIBA testing.

[Correlation between hepatitis C virus (HVC) RNA and anti-HVC antibodies in a hemodialysis population]. / Corrélation entre l'ARN du virus de l'hépatite C (VHC) et les anticorps anti-VHC dans une population d'hémodialysés.

Polymerase chain reaction (PCR) was applied to detect HCV-RNA in 75 hemodialyzed patients. Anti-HCV status was determined by ELISA-2 and by RIBA-2 for reactive samples by ELISA. ALT levels were monthly determined during the year preceding the end of the study. For 60 patients, anti-HCV serology was known since 1989 and 39 of them were tested for the presence of HCV-RNA at least four times during the 2 preceding years. The 9 patients who were negative for anti-HCV antibodies were negative by PCR. Of the 7 patients with an indeterminate profile by RIBA-2, 3 were positive by PCR: 1/1 with C-33c band only and 2/6 with C22-3 band only. Of the 59 patients reactive by RlBA-2, 57 were HCV-RNA positive. Of the 2 HCV-RNA negative patients, one had been PCR positive before interferon therapy. Of the 38 patients without acute hepatitis tested by PCR on 5 successive samples, all the specimens of 11 and 23 patients were HCV-RNA negative and HCV-RNA positive respectively. In 4 patients, a transient viremia was observed. The group of HCV-RNA positive patients had mean ALT levels greater than those who were negative. A correlation was established between HCV infection and both the time on dialysis and the number of blood transfusions. A high concordance (97%) was observed between antibodies to HCV and HCV-RNA.

Detection of hepatitis C virus by polym erase chain reaction in haemodialysed patients in relationship to anti-HCV status.

HCV RNA was determined by the polymerase chain reaction (PCR) in 41 haemodialysed patients with a known anti-HCV status (ELISA and RIBA-2) and a monthly alanine aminotransferase (ALT) level determination. No histological examination of the liver tissue was available. Four samples from each patient were collected at 6 month intervals for 18 months. Seven patients negative for anti-HCV during the entire follow-up gave negative PCR results on the four samples. Two patients who were anti-HCV-negative upon entry into the study seroconverted to HCV during follow-up. HCV RNA was detected during the acute phase of hepatitis. HCV RNA was no longer detectable after antiviral therapy was administered to one patient. Out of 27 anti-HCV-positive patients, 24 had persistent viraemia, 2 had transient viraemia (1 sample PCR-negative and 3 samples PCR-positive) and 1 was PCR-negative on the 4 samples. Thirteen of the 26 viraemic patients had a normal ALT level during the preceding 3 years. Three patients with a C22-3 band alone by RIBA-2 were negative by PCR, whereas two patients with a C33-c band alone were PCR-positive on the four samples. These results suggest that HCV viraemia was strongly associated with anti-HCV in haemodialysed patients with or without biological hepatitis.

The use of hepatitis B vaccine as booster for donors immune to HBV for the production of hepatitis B immunoglobulin (HBIG).

Forty nine blood donors immune to HBV volunteered to receive a single dose of hepatitis B vaccine (HEVAC B from Institut Pasteur Production). The initial mean level of anti-HBs was 20 IU/ml (from 5 to 75 IU/ml). The maximum level was observed at the consecutive plasma donation usually 1 month and a half after the vaccine injection. The mean maximum level was 188 IU/ml (from 7 to 800 IU/ml) i.e. an increase of 9 times the initial level. Six donors developed a very weak immune response (inferior to twice the initial level). In the 43 others, anti-HBs levels remained higher than initial level 6 months after the vaccine injection. One year later (study conducted in 25 subjects) 56% had anti-HBs levels superior to 3.6 to 16 times the original level. Such booster responses are of considerable practical importance for increasing anti-HBs titers in human donors for producing HBIG.

[Use of hepatitis B virus vaccine in volunteer donors already immunized against this virus]. / Utilisation du vaccin contre le virus B de l'hépatite chez les donneurs bénévoles déjà immunisés contre ce virus.

Forty nine blood donors immune to HBV have been volunteers to receive a single dose of hepatitis B vaccine (Hevac B from Pasteur Institute Production). The initial mean level of anti-HBs was 20 IU/ml (from 5 to 75 IU/ml). The maximum level was observed at the consecutive plasma donation usually 1 month and a half after the vaccine injection. The mean maximum level was 188 IU/ml (from 7 to 800 IU/ml). i.e. an increase of 9 times the initial level. Six donors have developed a very weak immune response (inferior to twice the initial level). In the 43 others, anti-HBs levels remained higher than initial level 6 months after the vaccine injection. One year later (study conducted in 25 subjects), 56% had anti-HBs levels superior to 3.6 to 16 times the original level. Such booster responses are of considerable practical importance for increasing anti-HBs titers in human donors for producing HBIG.